Late Santonian-Early Campanian Research Articles

Late Mesozoic Tectono-stratigraphic evolution of the Hekimhan Basin and the environs (central eastern Anatolia): implications for the eastern Taurides and Gürün Curl

ABSTRACT The east-west trending Taurides form a curved area in central eastern Anatolia known as the Gürün Curl. In order to understand the origin of the Gürün Curl and Tauride evolution in general, the results of a new field study of this region have been synthesized together with previously published data. We suggest that the geodynamic evolution of the area began with the likely presence of a Tethys Ocean transform fault. This fault separated the Taurides into the Akdere Sector in the west and the Munzur Sector in the east in the Late Cretaceous. During the late Santonian–early Campanian, ophiolites obducted onto the Munzur Sector, while platform sediments continued to accumulate in the Akdere Sector. This was followed by the development of an Andean-type arc-type magmatism (the Baskil Arc) during the early–middle Campanian in the Munzur Sector. Continued closure of the Tethys led to the collision of the Bitlis Massif in the south of the Munzur Sector in the Campanian. This, in turn, resulted in continental subduction and slab roll-back that was controlled by a Subduction Transform Edge Propagator (STEP) Fault that lay on the original transform fault between the Akdere and Munzur sectors. Because the subducted slab was free at its western corner, the western edge rolled back faster than in the east, leading to an asymmetrical extensional regime on the upper plate that created the late Campanian Hekimhan Basin. While these geodynamic events were taking place in the Munzur Sector, the Akdere Sector was in a platform setting. During the Palaeocene, the Late Mesozoic units of the Akdere Sector began to overthrust on the Hekimhan Basin and the ophiolites. Following the Palaeocene, all these tectonostratigraphic units were covered by Eocene sediments around the Gürün Curl of which the modern appearance was completed by the Miocene to Recent movements along the strike-slip faults.

Correlation of the late Santonian-early Campanian of Texas, USA with the Anglo-Paris Basin (United Kingdom) and other regions

Correlation of the late Santonian-early Campanian of Texas, USA with the Anglo-Paris Basin (United Kingdom) and other regions

Changes in biogeographic distribution patterns of southern mid-to high latitude planktonic foraminifera during the Late Cretaceous hot to cool greenhouse climate transition

The biogeographic distribution of planktonic foraminifera from southern mid-to high latitudes region are discussed to identify links between species distribution patterns and the changes in Late Cretaceous climate. We present relative abundance data for planktonic foraminifera spanning from the hot greenhouse climate of the Turonian to the cooler greenhouse of the Maastrichtian based on study of Ocean Drilling Program (ODP) holes 690C (Maud Rise), 700B (Northeast Georgia Rise), 1138A (Kerguelen Plateau) and 762C (Exmouth Plateau). These drill sites were located between 47° and 65°S paleolatitude in the southern South Atlantic and southern Indian Ocean where there is a good record of changes in vertical gradients and sea surface temperatures (SSTs) and shifts are well expressed due to amplification of global climatic variations in the circum-Antarctic region.The stratigraphic distribution of planktonic foraminiferal marker species that consistently occur at all sites enables construction of a new biozonation scheme that is applicable to the southern mid-to high latitude region. Quantitative data from planktonic foraminifera are used to examine variation in assemblage composition, permitting interpretation of changes in the patterns of surface water stratification. In addition, temporal biogeographic patterns are documented from the stratigraphic record of endemic species of the Southern Ocean and of species displaying poleward or equatorward migration.Results indicate that the broadest latitudinal expansion of the Tethyan tropical climatic belt coincided with the highest paleotemperatures of the Turonian–Santonian. The onset of significant sea surface temperature cooling in the late Santonian–early Campanian led to a progressive increase in the latitudinal temperature gradient and greater biogeographic differentiation among planktonic foraminiferal assemblages. These trends resulted in the establishment of a Transitional Bioprovince with Tethyan and Austral affinities in the southern latitudes that persisted through the Campanian and Maastrichtian and the development of a well-defined Austral Bioprovince that is observed by the early Maastrichtian at paleolatitudes south of 60°S.

Characteristics of Radiolarian Evolution in the Campanian and Maastrichtian and Prospects for Detailed Stratigraphy

The Campanian and Maastrichtian radiolarian assemblages are known from many regions of the Tethyan Superrealm. Unfortunately, only some of them are reliably dated and completely studied as paleontological assemblages. The analysis of evolution of radiolarians is based on Campanian to Maastrichtian assemblages from Crimea, Cyprus, and Serbia properly dated and studied in detail with addition of data from California, Turkey, the World Ocean, and other regions. It is concluded that renewal of assemblages took place in the Campanian and Maastrichtian relatively slowly. The biodiversity was slowly reduced at the generic level. The history of radiolarian evolution in the end of the Late Cretaceous can be subdivided to several stages: late Santonian–early Campanian, early Campanian–late Campanian, late Campanian–early Maastrichtian, and late Maastrichtian.

Late Santonian-early Campanian lake-level fluctuations in the Songliao Basin, NE China and their relationship to coeval eustatic changes

In contrast to glacio-eustasy, which is mainly controlled by the waxing and waning of continental ice sheets during icehouse climate stages, the concept of aquifer or limno-eustasy suggests that the effects of groundwater storage and release may have been the main driver of short-term (10s kyr to a few Myr) sea-level changes in the Cretaceous ice-free world. Presumably climate-controlled hydrological cycling could change the water volumes of continental reservoirs and oceans by transporting water between continents and oceans, resulting in out-of-phase relation between lake and sea levels.In the present study, we present lake-level fluctuations in Members 1 and 2 of the Nenjiang Formation (late Santonian-early Campanian) in the Songliao Basin that are indicated by basin-scale correlations of Fischer Plots based on natural gamma-ray logging data. Meanwhile, the Al/K ratios of the SK1 core indicate that changes in precipitation forced lake-level fluctuations in the basin. Compared to global sea-level changes, lake-level fluctuations show an out-of-phase relation with sea-level variations in the lacustrine phase of the basin, suggesting that climate-driven water transport between continents and oceans controlled short-term sea-level changes in the late Santonian-early Campanian. During the phase of marine-lake connectivity (basal Nenjiang Member 1), although the marine regression-driven decrease in lake-level corresponds to salinity stratification and strongly reducing water conditions, increasing precipitation in the basin implies that the hydrological cycle transported more water from the oceans toward continents. Based on the results we suggest that limno-eustasy controlled water levels in the Songliao basin in the late Santonian-early Campanian.

Late Cretaceous tectono-sedimentary events in NW Europe

Late Cretaceous sedimentary history has been strongly influenced by both sea-level fluctuations and inversion tectonics. Evidence for tectonic movements, originally identified in German Late Cretaceous basins, is applied to the UK successions. Two periods of movement are conspicuous: a Middle Turonian episode involving huge loss of section along anticlinal axes in southern England and a Late Santonian-Early Campanian episode also involving section loss on structure and section gain off structure. This pattern is repeated where folds or blocks are underlain by inversion thrust faults (e.g. the Purbeck Fault in Dorset, the Falmer Fault in Sussex, the Portsdown Fault in Hampshire and the Bray Fault in Upper Normandy). Other episodes of inversion in the Late Turonian to Middle Coniacian and the late Early Campanian are investigated and are a probable cause of slump beds and slides. These tecto-sedimentary episodes can be applied to structures in Northern Ireland, Inner Hebrides, North Sea and Yorkshire as well as southern Britain. Beyond NW Europe the Late Santonian – Early Campanian event is widely recognised in the Carpathians, southern Europe, Africa and the Levant and coincides with the end of the Long Cretaceous Quiet Zone (Chron 34N to 33R) perhaps representing a major change in Earth dynamics related to Mid-Ocean Ridge crustal production and intra-continental crust tectonism.

Silicoflagellate double skeletons in the geologic record

Abstract Modern silicoflagellates are known to produce double skeletons, which are considered as pre-division stages; members of modern doublets are aligned at basal corners, using either pikes or organic material between the abbasal surfaces of the basal rings to hold together. In contrast, fossil doublets from the Cretaceous and Paleogene often have the corners of each skeleton oriented between those of the paired member in what is known as the Star-of-David configuration. Until recently, however, virtually nothing was known about the fine structure of fossil double skeletons. As a follow-up to our recent study on extant silicoflagellate doublets, we present a compilation of data on the fossil record of silicoflagellate double skeletons, with particular focus on the Cretaceous and Paleogene. Fossil silicoflagellate double skeleton specimens are extremely rare, with the oldest being from the late Santonian–early Campanian. In order to test whether silicoflagellates may have produced doublets prior to that time, we have constructed three-dimensional computer models of silicoflagellate double skeleton morphologies. Our findings indicate that doublet formation was part of the silicoflagellate reproductive cycle already since early in the evolutionary history of the group, before the development of the basal ring. Two distinct double skeleton configurations developed at some point in this evolution, with the Star-of-David group likely becoming extinct in the Oligocene, and the corner-aligned group represented by the Neogene and modern silicoflagellates. At present, the doublet configuration in fossil silicoflagellates can only be determined confidently with paired skeletons, but the occurrence, position and orientation of pikes may offer useful clues to interpret the doublet configuration from single skeletons. Unusual pike morphologies of some silicoflagellates from the Eocene strongly suggest a Star-of-David configuration. Silicoflagellate skeletal morphologies with pikes appear to be less abundant in the fossil record as double skeletons, and may disassociate more readily than morphologies that lack pikes and are instead held together by organic material between the basal rings.

Bertilanthus scanicus, a New Asterid Flower from the Late Cretaceous (Late Santonian–Early Campanian) of Scania, Sweden

A new genus and species of fossil flowers, Bertilanthus scanicus, is described from the Late Cretaceous of southern Sweden. The flowers of B. scanicus are actinomorphic and bisexual with an inferior ovary. Perianth and androecium are pentamerous. The sepals are small and free, and calyx aestivation is apert; petals are larger, and aestivation of corolla is imbricate. The androecium consists of a single whorl of stamens opposite the petals. The anthers are dithecate, tetrasporangiate, sagittate, and dorsifixed. Pollen observed in the flower is minute and oblate to spheroidal with three colpi and a tectate-punctate pollen wall. The gynoecium is formed from two carpels, and there are two free and stout styles. The epidermal cells of the styles are palisade shaped and form a distinct radiating pattern. The ovary is unilocular with numerous anatropous ovules borne on two intruding parietal placentae. There is a distinct five-parted nectary disk inserted between perianth and styles. The fruit was probably dry and capsular with apical dehiscence between the styles. Bertilanthus scanicus shares the presence of the unusual radiating palisade cells of the styles with Silvianthemum suecicum, another taxon described from the Åsen locality based on fossil flowers. Other critical features shared between Bertilanthus and Silvianthemum, including minute, tectate-punctate pollen, papillate-spiny extension of the palisade cells, free and stout styles, unilocular ovary, parietal placentation with placentae extending almost to the center of the ovary, and numerous anatropous ovules with reticulate surface, indicate that the two genera are closely related and also link these fossils to extant Quintinia, currently placed in the Paracryphiaceae (Paracryphiales) in the asterid clade.

Позднемеловая флора Хатангской впадины (северная Сибирь)

Fossil plants from the Late Cretaceous deposits of the Khatanga depression are joined in three floristic assemblages: the Ledyanaya assemblage (the Turonian-Coniacian), the Kheta assemblage (the late Coniacian-early Santonian) and Mutino assemblage (the late Santonian-early Campanian). The Ledyanaya floristic assemblage contains ferns (Anemia rarinervis Abramova), cycadophytes (Nilssonia sp.), ginkgoales (Ginkgo ex gr. sibirica Heer), conifers (Taxodium sp., Sequoia tenuifolia (Schmalh.) Sveshn. et Budants.) and angiosperms (Pseudoprotophyllum hatangaense Abramova, Liriodendropsis simplex (Newb.) Newb., Trochodendroides sp., ะกissites sp., Dicotylophyllum sp.). The characteristic features of this assemblage are depauperated composition of angiosperms and survival of the Early Cretaceous relic elements. The Kheta floristic assemblage contains only Taxodium sp. and Trochodendroides sp. The Mutino floristic assemblage contains Sequoia tenuifolia, Pseudoprotophyllum hatangaense, Quereuxia angulata (Newb.) Krysht. ex Baik. and Cobbania corrugata (Lesq.) Stockey, Rothwell et Johnson. The Ledyanaya floristic assemblage is very similar with the Newsiberian flora from the Derevyannye Gory Formation of New Siberia Island. The Mutino floristic assemblage have common elements with Kundur flora (the Campanian) from the Kundur Formation of Amur region. The abundance of large leaves of Pseudoprotophyllum in the Mutino flora is evidence of the preservation of humid warm-temperate climate in the northern part of Siberia up to the Campanian. The presence of water plants Quereuxia angulata and Cobbania corrugada indicates the westward migration of some characteristic elements of the Pacific ocean lowlands.

The Late Cretaceous shark Ptychodus marginalis in the Western Interior Seaway, USA

Re-evaluation of teeth referred to the Late Cretaceous shark Ptychodus polygyrus from North America are hereby determined to be synonymous with another species having similar tooth morphology, Ptychodus marginalis Agassiz. Ptychodus marginalis differs from P. polygyrus by having an elevated and rounded tooth crown with transverse ridges restricted centrally on the apex of the crown with a clearly defined marginal area. The type specimen of P. marginalis was described from Middle Cenomanian to Middle Turonian deposits in the English Chalk, and teeth possessing identical tooth morphologies are found within contemporary units in North America, whereas teeth having the typical P. polygyrus morphology are restricted to Late Santonian-Early Campanian deposits.

Fossil Record and Age of the Asteridae

The Asteridae is a group of some 80,000 species of flowering plants characterized by their fused corollas and iridoid compounds. Recent phylogenetic analyses have helped delimit the group and have identified four main clades within it; Cornales, Ericales, Lamiids and Campanulids, with the last two collectively known as the Euasteridae. A search for the oldest fossils representing asterids yielded a total of 261 records. Each of these fossils was evaluated as to the reliability of its identification. The oldest accepted fossils for each clade were used to estimate minimum ages for the whole of the Asteridae. The results suggest that the Asteridae dates back to at least the Turonian, Late Cretaceous (89.3 mya) and that by the Late Santonian-Early Campanian (83.5 mya) its four main clades were already represented in the fossil record.

Integrated Late Santonian-Early Campanian sequence stratigraphy, New Jersey Coastal Plain: Implications for global sea-level studies

Recent studies of the Santonian-lower Campanian section (Merchantville Formation) in two coreholes (Ancora and Bass River) from the New Jersey coastal plain postulated the existence of concatenated sequences in glauconitic facies (Miller et al. 2004). The lithologic expression of unconformities within the Merchantville glauconitic sediments is obscure and their resolution requires an integrated stratigraphic approach. Here, we present detailed litho-and biostratigraphic analyses of the Merchantville Formation sequences in four New Jersey coastal plain coreholes (Sea Girt, Ancora, Millville, and Bass River). Biofacies analysis reveals four benthic foraminiferal assemblages from inner to middle neritic environments. Correlation of benthic foraminiferal biofacies, percentage of planktonic foraminifera, and lithologic data indicates that paleowater depths varied between 30 and 75m. The correlation of biostratigraphy, benthic foraminiferal biofacies, lithology, and gamma logs delineates unconformities, and identifies three sequences within the Merchantville Formation (MeI, MeII, MeIII). The ages of these sequences have been constrained by calcareous nannoplankton biostratigraphy (MeI: CC16; MeII: CC17-18; MeIII: CC18-19) from 78.8 to 84.5 Ma. The Merchantville I sequence is observed in the Sea Girt and Bass River coreholes. The Merchantville II and III sequences are present throughout the New Jersey coastal plain, and the ages of the Merchantville II and III sequences boundaries are similar to those of North Carolina, and North-Western Europe suggesting an interregional cause of sequences boundaries. Comparison of the New Jersey shallow marine sequences with the deep-sea record from DSDP Site 511 (Falkland Plateau) show that the episodes of sea-level fall in New Jersey are synchronous with 18O increases. Our data imply that the Merchantville sequence boundaries may be attributed to ice volume increases and support the contention that global sea-level changes were controlled by ice-volume variations even during the peak warmth of the Cretaceous.

Cretaceous foraminiferal biostratigraphy and palaeoecology of Ikomo-1 well, Calabar flank, southeastern Nigeria

The Cretaceous sediments in Ikono-1 well, Calabar Flank, consist of a sequence about 1,878 m thick of calcareous sandy shale (Uppermost Mfamosing limestone Formation) at the base, overlain by continuous alternating sequence of black to dark and light grey shales with sandstone (Nkalagu Formation) and calcareous black fissile shale (Nkporo Shale) at the top. The sediments are fossiliferous and were deposited in a shallow inner neritic environment of less than 50 m. depth. Two marine transgressions were recognized, the Cenomanian-Turonian and Early Senonian transgressions. The Cenomanian is recognized by the presence of Hedbergella delrioensis, Hedbergella planispira, Rotalipora balernaensis, Trochammina sp. and Dorothia oxycona, while the Turonian-Santonian stage is characterized by the abundance of Heterohelix reussi, Heterohelix ultimatumida, Praebulimina fang, Gavelinella guineana, Nonionella robusta and Whiteinella baltica. Foraminifera indicative of Late Santonian-Early Campanian were not recovered, thus a period of erosion and/or non-deposition is suggested. Diagnostic species of Campanian-Maestrichtian age (Nkporo shale) are Globotruncana gansseri, Afrobolivina afra, Buliminella brevispira, and Globigerinelloides multispinatus.

The stratigraphy of the Chalk Group (Upper Cretaceous) of the Gipping Valley, near Ipswich, Suffolk, UK

The Chalk outcrops in the Gipping Valley, northwest of Ipswich are of great significance in providing a rare glimpse of the often Drift-covered inland East Anglian Chalk succession. The exposures show an unusually thick development of virtually flintless and virtually marl-free chalk, unlike any chalk seen elsewhere in the UK. Macrofossil and microfossil data show that this chalk belongs to the Marsupites testudinarius and O ffaster pilula macrofossil zones, and is coeval with the Newhaven Chalk Formation of southern England. The Uintacrinus anglicus Zone appears to be absent. This chalk is herein named the Blakenham Chalk, provisionally regarded as a Member of the Newhaven Chalk Formation. Similar, virtually flintless chalk, up to 63.5 m thick, occurs in boreholes in Ipswich, beneath a variable cover of Cenozoic and Quaternary strata. This chalk belongs to the basal Gonioteuthis quadrata Zone, and extends down through the O. pilula, M. testudinarius, Uintacrinus socialis and topmost Micraster coranguinum zones, equivalent to the Newhaven Chalk and topmost Seaford Chalk formations of southern England. At outcrop and in boreholes, the virtually flintless chalk is overlain by regularly flinty chalk, up to 8.5 m thick. Macrofossil data show that this chalk belongs to the lower part of the G. quadrata Zone, and that records of Belemnitella from this interval probably correlate with an acme of this belemnite in the lower G. quadrata Zone of southern England. Microfossil data are more equivocal, but this may reflect unusual environmental conditions. Lithostratigraphically, the flinty chalk succession is correlated with the lower part of the Culver Chalk Formation of southern England. The unusual lithology of the Blakenham Chalk Member may reflect the influence of local structural highs rejuvenated by Late Santonian-Early Campanian (Wernigerode Phase) tectonism.

Mammals from the Upper Cretaceous Aitym Formation, Kyzylkum Desert, Uzbekistan

The Upper Cretaceous (?Santonian) Aitym Formation in the central Kyzylkum Desert, Uzbekistan, produced remains of a cimolodontan multituberculate ( Uzbekbaatar wardi), a spalacotheriid symmetrodont (cf. Shalbaatar sp.), a deltatheroidan (cf. Deltatherus sp.), possibly the asioryctithere aff. Daulestes sp., possibly two zalambdalestids ( Kulbeckia sp. cf. K. kulbecke and aff. Kulbeckia sp.), two supposed lipotyphlans ( Paranyctoides sp. cf. P. aralensis and Paranyctoides sp.), and zhelestid ungulatomorphs (cf. Aspanlestes sp., Parazhelestes sp. aff. P. minor, Parazhelestes sp. cf. P. robustus, and Eoungulatum sp. cf. E. kudukensis). The Aitym mammal fauna is most similar to the more diverse mammal fauna of the underlying Bissekty Formation (upper Turonian–Coniacian). Uzbekbaatar and Shalbaatar were most probably derived from North American immigrants. Paranyctoides and ‘Zhelestidae' are of Middle Asian (a commonly and long used Soviet geographic region approximately extending from the Caspian Sea on the west to the Chinese border on the east, and from the Iranian and Afghan borders on the south to southern Kazakhstan on the north) origin and migrated to North America during the late Santonian–early Campanian. A dispersal route was present in Beringia during the entire Late Cretaceous, which may have worked as a cold filter, allowing intercontinental dispersals between Asia and western North America in both directions, especially during shorter, warm climatic phases.

Stratigraphic distribution and habitat segregation of mosasaurs in the Upper Cretaceous of western and central Alabama, with an historical review of alabama mosasaur discoveries

ABSTRACT A survey of mosasaur material from the Eutaw Formation (Santonian) and Selma Group (Late Santonian–Late Maastrichtian) of western and central Alabama has revealed significant stratigraphic segregation among taxa. Three distinct biozones are recognized based on this survey: the Tylosaurus Acme-zone (from the base of the Tombigbee Sand Member of the Eutaw Formation to approximately 12 m above the base of the Mooreville Chalk), the Clidastes Acme-zone (from approximately 12 m above the base of the Mooreville Chalk to the base of the Demopolis Chalk), and the Mosasaurus Acme-zone (from the base of the Demopolis Chalk to the K-T boundary at the top of the Prairie Bluff Chalk). In each case, the biozone is named for the genus comprising the majority of the specimens examined from that horizon. The previously-recognized Glohidens alabamaensis Acme-zone, including the Arcola Limestone Member of the Mooreville Chalk, has been abandoned. The transition from the Tylosaurus biozone to the Clidastes biozone has been interpreted primarily as an artifact of paleoecology, reflecting habitat preference; additional support for this interpretation has come from the mosasaur fauna of the Blufftown Formation (?Late Santonian–Early Campanian) of eastern Alabama and western Georgia. The transition from the Clidastes biozone to the Mosasaurus biozone appears to represent the local expression of a reorganization within North American mosasaur communities. The uppermost portion of the Selma Group, comprised of the Ripley Formation and Prairie Bluff Chalk, has been tentatively included in the Mosasaurus Acme-zone on the basis of poorly-known faunas.

<i>Odontochitina tabulata</i> sp. nov. A Late Santonian–Early Campanian dinoflagellate cyst from SE Sirte Basin, Libya

Abstract. Odontochitina tabulata, a new tabulated ceratioid species, has been recorded and described from core samples in Well C3-65 in the SE Sirte Basin. This species is characterizd by parasutural and pandasutural features reflecting clear gonyaulacacean paratabulation. It has a short stratigraphic range and is considered as a valuable stratigraphic marker for the Late Santonian–Early Campanian. The diagnosis of the genus Odontochitina Deflandre, 1935 is emended to include forms having a well defined gonyaulacacean paratabulation and narrow pandasutural and parasutural ridges.

Upper Cretaceous tectonic phases and end Cretaceous inversion in the Chalk of the Anglo-Paris Basin

Three intra-Upper Cretaceous tectonic phases, Stille's Ilsede (Late Turonian-Early Coniacian), Wernigerode (Late Santonian-Early Campanian) and Riedel's Peine (latest Lower Campanian) are investigated in the Anglo-Paris Basin. Criteria for recognizing these events include field evidence of slumping, allochthonous chalks; lateral changes in thickness and lithology; seismic evidence for slump horizons; and lacunae closely related to tectonic axes. Further evidence from seismic sections indicates large-scale channel development during these phases but the spatial relationship with tectonic lineaments is more difficult to determine. Each phase rejuvenates the tectonic topography which is subsequently buried by post-tectonic facies changes, for example from Lewes to Seaford Chalk following the Ilsede tectonic phase and Culver to Portsdown Chalk, following the Peine tectonic phase. The tectonic phases are recognized along local tectonic lineaments in contrast to more widespread sea-level fluctuations. New information on the end Cretaceous inversion in the London and Anglo-Paris basins supports the recognition of a London axis of uplift where the chalk at subcrop was more deeply eroded than at outcrop. Maximum inversion in the Weald-Wessex area occurred in East Sussex along the southern margin of the Weald where the thickest chalks had previously been deposited.

Campanian Bolivinoides and microfacies from the La Luna Formation, western Venezuela

Tres Esquinas, the upper member of the La Luna Formation, a 1–3 m thick condensed sequence composed of glauconitic phosphorite, signals the commencement of the Late Cretaceous regression in western Venezuela.This is the last of a series of thin phosphatic beds, the others non-glauconitic, occurring in the upper La Luna Formation. In the State of Mérida, the presence of Bolivinoides culverensis restricts these phosphatic beds to the late Santonian-early Campanian, with the Tres Esquinas Member assigned to the Globotruncanita elevata-Globotruncana ventricosa Zones. Bolivinoides sp. cf. B. sirticus is also commonly found in these beds.Although no Bolivinoides have been detected in the Tres Esquinas Member in the State of Táchira to the west, the non-glauconitic phosphate bed, informally named “Capa II”, as well as the 15 m thick Ftanita de Táchira Member which underlies the Tres Esquinas Member and separates it from “Capa II”, contain Bolivinoides culverensis as well as Bolivinoides cf. B. sirticus. This occurrence, combined with the assignation of the base of the overlying Colon Formation to the Globotrucana aegyptiaca Zone, suggests a late Campanian age for the member in this area, and implies that the member is diachronous.On the basis of lithology, mineralogy, foraminiferal content, and degree of bioturbation, six microfacies and one sub-microfacies are identified. The microfacies of the phosphatic limestones containing Bolivinoides spp. are notably different in the two states.

Upper Cretaceous Magnoliaceous fruit from British Columbia

Litocarpon beardii is a multifolliculate fruit from the Upper Cretaceous Haslam Formation (late Santonian‐early Campanian) of British Columbia. About 19 follicles are helically arranged on an elongate, slender receptacle. Follicles are winged with the wing extending beyond the locule. Placentation is parietal along the ventral suture, and dehiscence was along the dorsal suture. Seeds are also winged and were derived from anatropous ovules. Affinities with the Magnoliaceae are suggested with Litocarpon combining characters of Magnolia and Liriodendron.